Climate change impacts

Glaciers

Climate science• The Greenhouse effect:

– Natural:• Water vapour

• Carbon dioxide

– Human produced:• Carbon dioxide

• Methane etc.

Human produced

A Question

What is the average temperature of the Earth?

1 metre above the surface and averaged over:• day and night, • all latitudes and longitudes.• all seasons

(a) – 15 ° C(b) – 5 ° C(c) + 5 ° C(d) + 15 °C

A Question

What is the average temperature of the Earth?

1 metre above the surface and averaged over:• day and night, • all latitudes and longitudes.• all seasons

(a) – 15 ° C(b) – 5 ° C(c) + 5 ° C(d) + 15 °C

Absorption bands

© Australian Bureau of MeteorologyWavelength

WaterAbsorption

CO2

Absorption

Infra Red

from EarthUV

from the Sun

Absorption bandsIllumination by the Sun

© Australian Bureau of MeteorologyWavelength

WaterAbsorption

CO2

Absorption

Infra RedUV

from the Sun

Absorption bandsRadiation from the Earth

© Australian Bureau of MeteorologyWavelength

WaterAbsorption

CO2

Absorption

Infra RedUV

from Earth(drawn on a different scale)

The transmittance of water vapour

VisibleInfra Red

The spectrum of sunlightInfra RedUV

Diagrams from : Bob Crowder The Wonders of the Weather Melbourne, Bureau of Meteorology 2000: p 22-23.

Sun

Earth

Emission spectra for the Sun and Earth

Climate science

• Interactions between EMR and the atmosphere:– Blackbody spectra– Sun and Earth

(but note that

Earth is less than

a millionth of

the Sun)

• Also note that the IR absorbed from the Sun is of much shorter wavelength than that emitted by the Earth

– UV Vis short IR – long IR

Climate Models: Results

What is the output of a climate model?

Courtesy of Graeme Pearman

Climate science• Interactions between EMR and the atmosphere:

– Types of spectra:

This is what we are This is what we are interested in.interested in.

• The effect of changes – Feedback and Forcing– H2O 95% should actually be 90-95% and is for

clouds also.– Can’t simply subtract leaving 5-10% for GHGs.– H2O and CO2 absorb different parts of the IR

radiation spectrum.

Climate Real science

H2O CO2

CH4

Climate Real science• The effect of changes – Feedback and Forcing

– Anthropogenic CO2 is NOT 3%!

The spectrum of sunlight

A family’s CO2 emissions

0.3 kg per km

4000

km per year

1200 kg CO2/year

0.3 kg per km per person

1000

km per year

600 kg CO2/year

0.5 kg per kWh

7300

kWh per year

3650 kg CO2/year

A family’s CO2 emissions

5450 kg of CO2 per year

Over 5 tonnes!

Observed changesBest estimates

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

1860 1880 1900 1920 1940 1960 1980 2000

Ano

mal

y (o C

)

Year

Expressing concernWhat can we do?

• Sustainable optionsThis is in sunny Germany!

Radiative forcing concentrations

Intergovernmental panel on Climate Change (2007) Climate Change 2007: The Physical Science Basis(Summary for Policymakers) Figure SPM2 p16: Radiative forcing componentsAccessed at www.ipcc.ch (11/5/2007)

Contributions toClimate Forcing

Greenhouse

gases

Carbon Dioxide

Methane

Chlorofluorocarbons

Nitrous Oxide

Ozone

Aerosols

Black Carbon

Reflective aerosols

Cloud droplet changes

Land cover changes

Sun

Climate Forcing (W/m2)0 +1-1

IPCC Predictions…

Methane concentrations

Intergovernmental panel on Climate Change (2007) Climate Change 2007: The Physical Science Basis(Summary for Policymakers)Figure SPM1 p15: Atmospheric concentration of CO2

Accessed at www.ipcc.ch (11/5/2007)

Carbon dioxide concentrations

Intergovernmental panel on Climate Change (2007) Climate Change 2007: The Physical Science Basis(Summary for Policymakers)Figure SPM1 p15: Atmospheric concentration of CO2

Accessed at www.ipcc.ch (11/5/2007)

Science behind the model

Greenhouse gases (2.5 Wm-2)

Emitted IR radiation

Natural greenhouse heating

Input solar radiation (100 %)

Reflected by clouds, atmosphere (~23%)

Reflected from surface (~8%) Absorbed by

ground (~49%)

Measured absorption(25%) ~80 Wm-2 ??

Absorbed by atmosphere (20%) ~60 Wm-2

Climate Models

Diagram from : Bob Crowder The Wonders of the Weather Melbourne, Bureau of Meteorology 2000: p 33.

Climate models have greatly improved

Modelled tropical cyclone

IPCC Predictions from Climate Research Unit,

East Anglia University

20080.5 metres in 100 years ?

1 metre

IPCC SynRep

Climate change impactsAustralia Temperature trend

Climate change impacts

According to NASA and the climate scientists.

Human induced changes• Is the climate changing?

IPCC SynRep

Carbon Cycle 760

90606.4

1.4

1.7

760 increasing at 3.2/year

2,000

39,000

500

1,000

3,000

300

Cause for concern

• Sceptics, deniers, avoiders– “We are in a cooling phase” Yes but…

Global CO2 Emissions

0

2

4

6

8

10

1990 1995 2000 2005 2010

Bill

ions

of t

onn

es

of C

arb

on

Developing Countries

Developed Countries

http://cdiac.ornl.gov/trends/emis/em_cont.htm

Total Global CO

2 Emissions

Figure 10.5

Figure 10.8

Figure 10.13

Figure 10.19

Figure 10.24

Figure 10.33

Figure 10.38

Box 10.2, Figure 2

• Most important greenhouse gas (ghg) is water vapour but its concentration is determined by temperature

• Important long-lived ghgs are CO2, CH4, N2O

• Absorption by ghgs seen in satellite infrared spectra• Absorption proportional to log(concentration), so

doubling ghg concentration gives same heating

Greenhouse effect

‘Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.’ (IPCC 2007)

Figure SPM.3

WGI Fig SPM.3

‘Global atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increasedmarkedly as a result of human activities since 1750 and now far exceed pre-industrial valuesdetermined from ice cores spanning many thousands of years.

The global increasesin carbon dioxide concentration are due primarily to fossil fuel use and land-use change, while those ofmethane and nitrous oxide are primarily due to agriculture.’

Figure SPM.1WGI Fig SPM.1

Sea ice in Sept 2007

From Stroeve et al, GRL, 2007

Sept 2005

Observed and projected Australian rainfall

Best estimate projected rainfall change for 2070(from “Climate change in Australia”)

Observed trend in annual rainfall

1970-2007

Projections of sea level risePast sea level and sea-level projections from 1990 to 2100 based on global mean temperature projections of the IPCC TAR.

From Rahmstorf, Science, 2007

From IPCC AR4

Stabilisation scenarios

best estimate

Likely range of climate sensitivity

best estimate

Likely range of climate sensitivity

• 455 ppm CO2-eq in 2005, 379 ppm CO2 conc

• I: CO2-eq stabilisation at 445-490 ppm, emissions peak in 2000-2015, global CO2 emissions -85% to -50% in 2050, warming of 2.0 to 2.4C above pi

• II: CO2-eq stabilisation at 490-535 ppm, emissions peak in 2000-2020, global CO2 emissions -60% to -30% in 2050, warming of 2.4 to 2.8C above pi

• Assuming equal per capita emissions, 50% global emission reduction in 2050 means ~90% emission reduction for US and Australia

SyR Fig SPM.11

Australian greenhouse gas emissions

Sector % change in 2010 in 2020Stationary energy +56% +64%Transport +42% +67Land use change -68% -68%Total +8% +20%

Australian emissions from energy use and transport have grown at more than 20% per decade. Australia is close to its Kyoto target only because of one-off reductions in land clearing.

Dept of Climate Change “Tracking to the Kyoto target 2007”

Other gases with greenhouse potential

Source, IPCC 4AR, SPM, 2007

Relative contribution to warming

Concentration Change per year

Radiative forcing Wm-2

<1700 2005

Carbon dioxide 275-285 379 ppmv 1.9 ppmv +1.66 ±0.17

Methane 715 1774 ppbv ~nil +0.48 ±0.05

Nitrous oxide 270 319 ppbv 0.83 ppbv +0.16 ±0.02

CFCs HCFCs Chlorocarbons

NA NA Slightly negative

+0.32 ±0.03

Ozone - stratosphere

- Troposphere

-0.05 ±0.10

+0.35 ±0.30

HFC, PFC, SF6 NA NA 10% +0.017 ±0.002

Total +2.63 ±0.26

Lifetime and global warming potentials of selected greenhouse gases

Gas Symbol Lifetime Years

Global Warming Potential

20-years 100-years

Carbon dioxide CO2 ~80 1 1

Methane CH4 12 72 25

Nitrous oxide N2O 114 289 298

CFC-11 CCl3F 45 3800 4750

CFC-12 CCl2F2 100 8100 10900

HFC-23 CHF3 270 11700 14800

Sulphur hexafluoride SF6 3200 23900 16300IPCC 4AR, Chapter 2, 2007

North Australian tropics annual sea surface temperature anomaly

(from1961-1990)http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/timeseries.cgi

Greenland Mass Loss – From Gravity Satellite

Global Mean Temperature

We stop all emissions NOW

We BEGIN to stop all emissions NOW

We do nothing

We BEGIN to stop all emissions EVENTUALLY

IPCC Predictions on Global Mean Temperature

Intergovernmental panel on Climate Change (2007) Climate Change 2007: The Physical Science Basis(Summary for Policymakers)Figure SPM3 p17: Observed changesAccessed at www.ipcc.ch (11/5/2007)

IPCC SynRep

IPCC SynRep

Feedback

GlobalTemperature

More Evaporation

Climate Forcing

Increased Climate Forcing

Increased Water

Vapour

Increased Cloud Cover

Decreased Climate Forcing

Negative

Positive

Sponsor Address Content

Aust. Acad. of Science

http://www.science.org.au/nova/ Carbon accounting, climate and health, biodiversity, health, etc.

Australian Bureau of Meteorology

http://www.bom.gov.au/climate/ Information about climate

http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/trendmaps.cgi Trends maps for Australia’s climat

http://www.greenhouse.gov.au/ Q and A, carbon accounting, energy

Australian Greenhouse Office

http://www.greenhouse.gov.au/ Q and A, carbon accounting, energy, etc

http://www.greenhouse.gov.au/inventory/2003/pubs/inventory2003.pdf Emission inventory

http://www.greenhouse.gov.au/education/tips.html What you can do

Hadley Centre, British Meteorological Office

http://www.metoffice.com/research/hadleycentre/pubs/brochures/ Publications

http://www.metoffice.com/research/hadleycentre/models/modeldata.html Climate predictions

http://www.metoffice.com/research/hadleycentre/obsdata/globaltemperature.html Global temperatures

CRC G/H Accoun.

http://www.greenhouse.crc.org.au/about%5Fgreenhouse/ Greenhosue, carbon accounting, impacts, etc.

CSIRO Marine and Atmospheric Research

http://www.cmar.csiro.au/e-print/open/gh_faq.htm#gh1 Greenhouse questions and answers

http://www.dar.csiro.au/capegrim/ghgasgraphs.html Greenhouse-gas levels, Cape Grim

http://www.dar.csiro.au/publications/projections2001.pdf Climate projections

Environment Canada

http://www.msc.ec.gc.ca/education/scienceofclimatechange/understanding/FAQ/FAQ-finalenglish.pdf

Greenhouse questions and answers

NOAA http://www.ncdc.noaa.gov/oa/climate/research/anomalies/anomalies.html Global data

Princeton University

http://www.princeton.edu/~cmi/resources/CMI_Resources_new_files/Environ_08-21a.pdf

Wedges approach to future energy options

Roy. Soc. London

http://www.royalsoc.ac.uk/downloaddoc.asp?id=1630 Facts and fiction about climate change

Concerned Scientists

http://www.ucsusa.org/global_warming/science/global-warming-faq.html Frequently asked questions

Vict. Government http://www.greenhouse.vic.gov.au/ Victorian greenhouse strategy, etc.

United Nations http://unfccc.int/2860.php Framework Convention on Climate Chnage

http://www.ipcc.ch/ Recent Fourth Assessment Report

Milankovitch Cycles

0

50

100

150

200

250

300

350

400

050100150200250300350400

CO

2 (p

pmv)

Thousands of years before the present

Note: Time scales are reversed

Figure prepared by Robert Rohde for Global Warming Art Project

1 metre per100 years

http://en.wikipedia.org/wiki/Sea_level_rise

Climate models

In brief, each is

• a complex, lengthy computer program,

• incorporating all physical/chemical and biological processes that drive weather and climate,

• reproducing the way in which climate behaves from day to day, and season to season.

What determines the Earth’s surface temperature?

For a detailed answer we need to know:

• How much light reaches the Earth?

• How much light reaches the Earth’s Surface?

• How much energy is radiated from the Earth’s Surface?

Climate models

• These are just

F = ma applied to moving fluids.

• This is conservation of mass.

• This governs the way heat flows between systems

Dieting Program

75.0

76.0

77.0

78.0

79.0

80.0

81.0

82.0

83.0

84.0

85.0

86.0

0 10 20 30 40 50 60 70 80 90 100

Days of Dieting

Weig

ht

(kg

)

Weight (kg)

12 Stone

13 Stone

Science behind the water cycle